Traditionally on Jackup Drilling Units, tubulars are taken from the horizontal position on a pipe deck, up through the V-door, and to a well center by manual handling via cranes, winches, and tuggers. The storage location is not a fixed distance from the well center, as the well center varies according to cantilever skid-out distance and transverse rotary table movement. Some improvements have been made over the years in pipe handling systems such as the introduction of column racking units, horizontal-to-vertical machines, and horizontal conveyors, but the efficiency of the overall functionality of drilling unit is still lacking, in part due to the fact that tubulars are usually stored on the fixed hull, but required on the moveable drill floor. The concept of keeping stored tubulars in a position of permanent fixity with respect to the drill floor has not been previously employed.
Embodiments of this invention streamline tubular handling on offshore drilling units by providing a simple, logical, streamlined system for storing, retrieving, and delivering tubulars in a controlled manner that is both repeatable and consistent. On a cantilever jackup unit, for example, the derrick and well are normally situated on the aft end. By storing pipe vertically, space is saved, and by doing so on the forward end of the cantilever on a jackup unit, the weight of the tubulars is also used as counterweight. The capability to build stands of pipe on the cantilever and then have them delivered vertically by a conveyor directly to the well center reduces risk to personnel by significantly reducing the number of tubulars that must be handled manually. By eliminating unnecessary motions in the process from storage to delivery, the logistical flow improvement translates directly to improved reliability and consistent tripping efficiency.
Embodiments of this invention simplify the processes of transporting and assembling tubulars by eliminating wasted movements. For example, pipe racking system (“PRS”) travel time is reduced going from the well center to a setback slot and back again as embodiments of the invention presents tubulars to the well center directly with no wait time. Further, the manual handling of tubulars is dangerous and can be inconsistent. Embodiments of this invention significantly minimizes human interface with moving tubulars and is a major step toward total automation of tubular handling.